Periodic table (crystal structure)

This articles gives the crystalline structures of the elements of the periodic table which have been produced in bulk at STP and at their melting point (while still solid) and predictions of the crystalline structures of the rest of the elements.

The following table gives the crystalline structure of the most thermodynamically stable form(s) for elements that are solid at standard temperature and pressure. Each element is shaded by a color representing its respective Bravais lattice, except that all orthorhombic lattices are grouped together.

Crystal structure of elements in the periodic table at standard temperature and pressure
1 H																		2 He
3 Li W	4 Be Mg												5 B β-B	6 C g-C	7 N	8 O	9 F	10 Ne
11 Na W	12 Mg Mg												13 Al Cu	14 Si d-C	15 P b-P	16 S α-S	17 Cl	18 Ar
19 K W	20 Ca Cu		21 Sc Mg	22 Ti Mg	23 V W	24 Cr W	25 Mn α-Mn	26 Fe W	27 Co Mg	28 Ni Cu	29 Cu Cu	30 Zn Mg	31 Ga α-Ga	32 Ge d-C	33 As α-As	34 Se γ-Se	35 Br	36 Kr
37 Rb W	38 Sr Cu		39 Y Mg	40 Zr Mg	41 Nb W	42 Mo W	43 Tc Mg	44 Ru Mg	45 Rh Cu	46 Pd Cu	47 Ag Cu	48 Cd Mg	49 In In	50 Sn β-Sn	51 Sb α-As	52 Te γ-Se	53 I Cl	54 Xe
55 Cs W	56 Ba W		71 Lu Mg	72 Hf Mg	73 Ta W	74 W W	75 Re Mg	76 Os Mg	77 Ir Cu	78 Pt Cu	79 Au Cu	80 Hg	81 Tl Mg	82 Pb Cu	83 Bi α-As	84 Po α-Po	85 At	86 Rn
87 Fr	88 Ra W		103 Lr	104 Rf	105 Db	106 Sg	107 Bh	108 Hs	109 Mt	110 Ds	111 Rg	112 Cn	113 Nh	114 Fl	115 Mc	116 Lv	117 Ts	118 Og
			57 La α-La	58 Ce α-La	59 Pr α-La	60 Nd α-La	61 Pm α-La	62 Sm α-Sm	63 Eu W	64 Gd Mg	65 Tb Mg	66 Dy Mg	67 Ho Mg	68 Er Mg	69 Tm Mg	70 Yb Cu
			89 Ac Cu	90 Th Cu	91 Pa α-Pa	92 U α-U	93 Np α-Np	94 Pu α-Pu	95 Am α-La	96 Cm α-La	97 Bk α-La	98 Cf α-La	99 Es Cu	100 Fm	101 Md	102 No

The following table gives the most stable crystalline structure of each element at its melting point at atmospheric pressure (H, He, N, O, F, Ne, Cl, Ar, Kr, Xe, and Rn are gases at STP; Br and Hg are liquids at STP.) Note that helium does not have a melting point at atmospheric pressure, but it adopts a magnesium-type hexagonal close-packed structure under high pressure.

Crystal structures of elements at their melting points at atmospheric pressure
1 H 13 K Mg																		2 He *
3 Li 453 K W	4 Be 1560 K W												5 B 2349 K β-B	6 C 3800 K g-C	7 N 63 K β-N	8 O 54 K γ-O	9 F 53 K γ-O	10 Ne 24 K Cu
11 Na 370 K W	12 Mg 923 K Mg												13 Al 933 K Cu	14 Si 1687 K d-C	15 P 883 K b-P	16 S 393 K β-S	17 Cl 171 K Cl	18 Ar 83 K Cu
19 K 336 K W	20 Ca 1115 K W		21 Sc 1814 K W	22 Ti 1941 K W	23 V 2183 K W	24 Cr 2180 K W	25 Mn 1519 K W	26 Fe 1811 K W	27 Co 1768 K Cu	28 Ni 1728 K Cu	29 Cu 1357 K Cu	30 Zn 692 K Mg	31 Ga 302 K α-Ga	32 Ge 1211 K d-C	33 As 1090 K b-P	34 Se 494 K γ-Se	35 Br 265 K Cl	36 Kr 115 K Cu
37 Rb 312 K W	38 Sr 1050 K W		39 Y 1799 K W	40 Zr 2128 K W	41 Nb 2750 K W	42 Mo 2896 K W	43 Tc 2430 K Mg	44 Ru 2607 K Mg	45 Rh 2237 K Cu	46 Pd 1828 K Cu	47 Ag 1234 K Cu	48 Cd 594 K Mg	49 In 429 K In	50 Sn 505 K β-Sn	51 Sb 903 K α-As	52 Te 722 K γ-Se	53 I 386 K Cl	54 Xe 161 K Cu
55 Cs 301 K W	56 Ba 1000 K W		71 Lu 1925 K Mg	72 Hf 2506 K W	73 Ta 3290 K W	74 W 3695 K W	75 Re 3459 K Mg	76 Os 3306 K Mg	77 Ir 2719 K Cu	78 Pt 2041 K Cu	79 Au 1337 K Cu	80 Hg 234 K α-Hg	81 Tl 557 K W	82 Pb 600 K Cu	83 Bi 544 K α-As	84 Po 527 K β-Po	85 At 575 K? ?	86 Rn 202 K ?
87 Fr 281 K? ?	88 Ra 973 K W		103 Lr 1900 K? ?	104 Rf ?	105 Db ?	106 Sg ?	107 Bh ?	108 Hs ?	109 Mt ?	110 Ds ?	111 Rg ?	112 Cn ?	113 Nh ?	114 Fl ?	115 Mc ?	116 Lv ?	117 Ts ?	118 Og ?
			57 La 1193 K W	58 Ce 1068 K W	59 Pr 1208 K W	60 Nd 1297 K W	61 Pm 1315 K W	62 Sm 1345 K W	63 Eu 1099 K W	64 Gd 1585 K W	65 Tb 1629 K W	66 Dy 1680 K W	67 Ho 1734 K Mg	68 Er 1802 K Mg	69 Tm 1818 K Mg	70 Yb 1097 K W
			89 Ac 1323 K Cu	90 Th 2115 K W	91 Pa 1841 K W	92 U 1405 K W	93 Np 917 K W	94 Pu 912 K W	95 Am 1449 K W	96 Cm 1613 K Cu	97 Bk 1259 K Cu	98 Cf 1173 K Cu	99 Es 1133 K Cu	100 Fm 1800 K? ?	101 Md 1100 K? ?	102 No 1100 K? ?

The following table give predictions for the crystalline structure of elements 85–87, 100–113 and 118; all but radon have not been produced in bulk. Most probably Cn and Fl would be liquids at STP (ignoring radioactive self-heating concerns). Calculations have difficulty replicating the experimentally known structures of the stable alkali metals, and the same problem affects Fr; nonetheless, it is probably isostructural to its lighter congeners. The latest predictions for Fl could not distinguish between FCC and HCP structures, which were predicted to be close in energy. No predictions are available for elements 115–117.

Predicted crystal structures of highly unstable elements
1 H																		2 He
3 Li	4 Be												5 B	6 C	7 N	8 O	9 F	10 Ne
11 Na	12 Mg												13 Al	14 Si	15 P	16 S	17 Cl	18 Ar
19 K	20 Ca		21 Sc	22 Ti	23 V	24 Cr	25 Mn	26 Fe	27 Co	28 Ni	29 Cu	30 Zn	31 Ga	32 Ge	33 As	34 Se	35 Br	36 Kr
37 Rb	38 Sr		39 Y	40 Zr	41 Nb	42 Mo	43 Tc	44 Ru	45 Rh	46 Pd	47 Ag	48 Cd	49 In	50 Sn	51 Sb	52 Te	53 I	54 Xe
55 Cs	56 Ba		71 Lu	72 Hf	73 Ta	74 W	75 Re	76 Os	77 Ir	78 Pt	79 Au	80 Hg	81 Tl	82 Pb	83 Bi	84 Po	85 At [Cu]	86 Rn [Cu]
87 Fr [W]	88 Ra		103 Lr [Mg]	104 Rf [Mg]	105 Db [W]	106 Sg [W]	107 Bh [Mg]	108 Hs [Mg]	109 Mt [Cu]	110 Ds [W]	111 Rg [W]	112 Cn [Mg]	113 Nh [Mg]	114 Fl	115 Mc	116 Lv	117 Ts	118 Og [Cu]
			57 La	58 Ce	59 Pr	60 Nd	61 Pm	62 Sm	63 Eu	64 Gd	65 Tb	66 Dy	67 Ho	68 Er	69 Tm	70 Yb
			89 Ac	90 Th	91 Pa	92 U	93 Np	94 Pu	95 Am	96 Cm	97 Bk	98 Cf	99 Es	100 Fm [Cu]	101 Md [Cu]	102 No [Cu]

The following is a list of structure types which appear in the tables above. Regarding the number of atoms in the unit cell, structures in the rhombohedral lattice system have a rhombohedral primitive cell and have trigonal point symmetry but are also often also described in terms of an equivalent but nonprimitive hexagonal unit cell with three times the volume and three times the number of atoms.

The observed crystal structures of many metals can be described as a nearly mathematical close-packing of equal spheres. A simple model for both of these is to assume that the metal atoms are spherical and are packed together as closely as possible. In closest packing, every atom has 12 equidistant nearest neighbours, and therefore a coordination number of 12. If the close packed structures are considered as being built of layers of spheres, then the difference between hexagonal close packing and face-centred cubic is how each layer is positioned relative to others. The following types can be viewed as a regular buildup of close-packed layers:

• Mg type (hexagonal close packing) has alternate layers positioned directly above/below each other: A,B,A,B,...
• Cu type (face-centered cubic) has every third layer directly above/below each other: A,B,C,A,B,C,...
• α-La type (double hexagonal close packing) has layers directly above/below each other, A,B,A,C,A,B,A,C,.... of period length 4 like an alternative mixture of fcc and hcp packing.
• α-Sm type has a period of 9 layers A,B,A,B,C,B,C,A,C,...

Precisely speaking, the structures of many of the elements in the groups above are slightly distorted from the ideal closest packing. While they retain the lattice symmetry as the ideal structure, they often have nonideal c/a ratios for their unit cell. Less precisely speaking, there are also other elements are nearly close-packed but have distortions which have at least one broken symmetry with respect to the close-packed structure:

• In type is slightly distorted from a cubic close packed structure
• α-Pa type is distorted from a hexagonal close packed structure

• Crystal structure
• Allotropy

General

• P.A. Sterne; A. Gonis; A.A. Borovoi, eds. (July 1996). "Actinides and the Environment". Proc. of the NATO Advanced Study Institute on Actinides and the Environment. NATO ASI Series. Maleme, Crete, Greece: Kluver Academic Publishers. pp. 59–61. ISBN 0-7923-4968-7.
• L.R. Morss; Norman M. Edelstein; Jean Fuger, eds. (2007). The Chemistry of the Actinide and Transactinide Elements (3rd ed.). Springer. ISBN 978-1402035555.

• Strukturbericht Type A – structure reports for the pure elements
• Crystal Structures for the solid chemical elements at 1 bar